Studies on Adenosine Triphosphate Transphosphorylases

Mahowald, Theodore A.; Noltmann, Ernst A.; Kuby, Stephen A.

doi:10.1016/s0021-9258(19)83737-7

Cited by 192 publications

(72 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One highly reactive sulfhydryl group per protomer has been found in all analyzed creatine kinases. Cytosolic isoforms chemically modified with several sulfhydryl-specific reagents were completely inactive [Mahowald et al, 1962;reviewed in Kenyon and Reed (1983)], but a few reagents tested allowed residual activity (Smith & Kenyon, 1974; der Terrossian & Kassab, 1976; Maggio et al, 1977). However, these latter findings have been challenged more recently by extensive studies suggesting that the reactive sulfhydryl group of CK is indeed essential for catalysis (Reddy & Watts, 1979;Wu et al, 1989; Zhou & Tsou, 1987).…”

mentioning

confidence: 99%

Creatine kinase: The reactive cysteine is required for synergism but is nonessential for catalysis

Furter¹,

Furter‐Graves²,

Wallimann³

1993

Biochemistry

117

116

View full text Add to dashboard Cite

Chemical modification of rabbit muscle creatine kinase (CK) with thiol-specific reagents led to partial or complete inactivation of the enzyme. Using site-directed mutagenesis, we have substituted the corresponding reactive Cys278 in the chicken cardiac mitochondrial creatine kinase (Mib-CK) with either glycine, serine, alanine, asparagine, or aspartate. The resulting mutant Mib-CK enzymes showed qualitatively similar changes in their enzymatic properties. In both directions of the CK reaction, a shift of the pH optimum to lower values was observed. Mutant Mib-CKs were severalfold more sensitive to inhibition by free ADP in the reverse reaction (ATP synthesis) and to free ATP in the forward reaction (phosphocreatine synthesis). With the exception of C278D, all mutant enzymes were specifically activated by chloride and bromide anions. C278D and wild-type Mib-CK were significantly inhibited under the same conditions. At low chloride concentrations, the Vmax of C278D was about 12-fold higher than that of C278N. Thus, Cys278 probably provides a negative charge which is directly or indirectly involved in maximizing CK activity. Under near-optimal conditions in the reverse reaction, mutants C278G and C278S showed about an 11-fold increase in Km(PCr), but only 1.7- and 2.8-fold reductions in Vmax, respectively, compared to wild-type Mib-CK. Thus, the reactive cysteine clearly is not essential for catalysis. For rabbit muscle CK, substrate binding had been shown to be synergistic (i.e., Kd > Km). We confirmed this finding for wild-type Mib-CK by determining the Kd and Km values for both substrates in the forward reaction.(ABSTRACT TRUNCATED AT 250 WORDS)

show abstract

mentioning

confidence: 99%

Creatine kinase: The reactive cysteine is required for synergism but is nonessential for catalysis

Furter¹,

Furter‐Graves²,

Wallimann³

1993

Biochemistry

117

116

View full text Add to dashboard Cite

show abstract

“…for c-aminocaproic acid. Mahowald & Kuby (1960) were unable to locate an N-terminus in creatine kinase, which suggests that lysine side chains may be responsiblefor the phenomenon observed. This is not incompatible with a pK near 9-0, as the pK is raised by 0-85 in the presence of the substrate equilibrium mixture.…”

Section: Discussionmentioning

confidence: 86%

“…This phenomenon has been investigated in greater detail. The reactive sulphydryl groups found to be essential for catalytic activity (Mahowald & Kuby, 1960;Watts, Rabin & Crook, 1961) appear to be the sites of inactivation. The results also provide evidence that these sulphydryl groups are situated close to the substrate-binding sites.…”

mentioning

confidence: 99%

STUDIES ON THE MECHANISM OF ACTION OF ADENOSINE 5′-TRIPHOSPHATE-CREATINE PHOSPHOTRANSFERASE. INHIBITION BY MANGANESE IONS AND BY P-NITROPHENYL ACETATE

Dc¹

1963

Biochemical Journal

View full text Add to dashboard Cite

“…Pathogenesis and mechanism of drug action: The present findings offer supportive evidence for the involvement of sulphydryl residues in the pathogenesis of muscular dystrophy and the mechanism of penicillamine action. In addition to glyceraldehyde 3-phosphate dehydrogenase, other glycolytic enzymes such as hexokinase, phosphofructokinase, and CPK require sulphydryl groups for maximal activity (Mahowald et al 1962) and are inactivated in dystrophic muscle. Penicillamine may protect these thiol enzymes and thereby promote more efficient production of adenosine 5'-triphosphate (ATP) and phosphocreatine.…”

Section: Discussionmentioning

confidence: 99%